The modern communications era has brought about a tremendous expansion of communication networks. Communication service providers and device manufacturers are continually challenged to deliver value and convenience to consumers by, for example, providing compelling network services, applications, and content. The developments of communication technologies have contributed to an insatiable desire for new functionality. Portable communication apparatuses (for example, mobile phones) are no longer just tasked with making telephone calls. With the increasing popularity and smartness of smart phones, mobile users rely on their smart phones more and more. Smart phones store various personal data such as email, message, location information, and some of them even bind a user payment account. Therefore, authentication of a user to use an apparatus such as a smart phone plays an important role in data security.